PHY SCI WEEK 1

• Oblate Spheroid


  Shape of the Earth, Has bulging equator and squeezed poles
• Lunar Eclipse

  • Anaxagoras observed the shadow Earth cast on the moon was circular, explained the causes phase of the moon
• Aristotle's argument supporting a spherical earth

  • Position of the north Star (Polaris)
  • The shape of the moon and sun
  • Ships disappearing over the horizon
• Eratosthenes


  Gave the most accurate size of the earth during their time (40,000 km)
• Aristarchus


  Proposed that the sun was the center of the universe (Heliocentrism)
• Hipparchus


  • Made a compilation of 850 stars
  • Developed a method for predicting lunar eclipses
• Claudius Ptolemy


  Believed that Earth was the center of the universe (Geocentrism)
• Ptolemaic system

  The geocentric model
• Babylonian and Egyptians


  Used a GNOMON in systematically observing the motion of the sun
• Phases of the moon

  • The shape of the moon in the night sky is dependent on the position of the earth and the light from the sun
• Lunar Eclipse


  Moon passes into the shadow of the earth
• Solar Eclipse

  Moon between the sun and Earth
• Diurnal Motion

  Daily revolution of celestial spheres
• Annual Motion


  Yearly movement of the sun
• Precession of Equinoxes

  Observable phenomena of the rotation of the heavens which spans a period of 25,920 years
• Planets Discovered before the invention of Telescope

  • Mercury
  • Venus
  • Mars
  • Jupiter
  • Saturn
• Tycho Brahe


  • Danish Astronomer who made accurate observations of the movement of celestial bodies (Geoheliocentric) or Tychanic
  • Catalogued 777 fixed stars in Denmark
• Johannes Kepler


  • German Astronomer
  • Tycho Brahe's Assistant
  • Kepler's 3 laws of planetary motion
• Kepler's 3 laws of planetary motion

  • Law of Ellipses: Planets follow an ellipse orbit, not circular, sun at one focus on the ellipse
  • Law of Equal Areas: straight line joining a planet and sweeps out equal areas in equal intervals of time
  • Law of Harmonies: Square of planet's orbital period is directly proportional to the cube of average distance from the sun